The present invention relates generally to railway hopper cars and, in particular, to door operating mechanisms for discharging material from bottom discharge hoppers.
A number of different types of railroad cars exist for hauling various types of bulk cargo and for discharging that cargo. For example, railway hopper cars carry coal, sand, aggregates and other loose materials which materials can be discharged through openings in hoppers located beneath such cars.
Generally, the hopper cars have a plurality of hoppers which store the cargo in readiness for discharge. A variety of door mechanisms are utilized to open and close material discharge openings formed in the bottoms of the hoppers. U.S. Pat. No. 2,600,357 discloses a door operating mechanism for a pair of longitudinally disposed discharge doors pivoted about generally horizontal axes which doors open and close an open bottom of a railway dump car. The doors are held closed by a latching mechanism and when the latch is released, the doors pivot downwardly to allow the material to exit the car. The doors are connected to a vertically upwardly extensible hydraulic actuator by cables for raising the doors to the closed position and holding the doors closed until the latching mechanism is actuated. Similar apparatuses are disclosed in U.S. Pat. Nos. 3,122,106; 3,596,608; 3,902,434; and 4,262,601. Also related to the door operating mechanisms shown in the aforementioned patents is U.S. Pat. No. 4,740,130 which shows a bottom discharge hopper having a body which is elevated by ramps so that the doors on the underside of the body can open outwardly and downwardly to permit material discharge from the body.
U.S. Pat. Nos. 3,173,381 and 2,729,503 disclose hoppers which utilize "clam shell" doors operated by separate actuators.
U.S. Pat. No. 3,786,764 discloses a commodity discharge car in which longitudinally spaced hoppers are closed by a pair of doors which overlap in a closed position approaching the horizontal. As the doors pivot open, they are rotated to a generally vertical position by a rack and pinion operating mechanism.
U.S. Pat. No. 4,452,149 discloses a door operating mechanism for a railway hopper car having doors with arcuate shaped sealing surfaces which doors are pivoted upwardly and outwardly to open a bottom discharge outlet of the hopper car. U.S. Pat. No. 4,114.785 discloses a similar rotary operated door mechanism for a hopper, with the doors having a generally planar body which is rotated downwardly.
U.S. Pat. No. 4,138,948 discloses a door operating mechanism in a side dump railway car which mechanism opens and closes outwardly movable discharge doors to discharge bulk material sideways from the hopper car.